package com.edu.bean;

public class B {

    private A a;

    public A getA() {
        return a;
    }

    public void setA(A a) {
        System.out.println("执行了 B里的 a属性的set方法");
        this.a = a;
    }

    public B() {
        System.out.println("执行了 B的构造方法");
    }
}
